Machines are commercially available for manufacturing box blanks, templates, etc. from a sheet of material. Such machines generally are called "sample makers" in the industry. Typically, they perform various manufacturing operations such as creasing, cutting, perforating, milling, marking, and similar operations on a sheet of material that is held on a table of the machine. Is some cases the sheet of material is tightly secured to a table, either by vacuum or by clamps and the tool is moved by means of an X-Y mechanism to perform the manufacturing operation on the upwardly facing surface of the material. In other cases the sheet of material is moved back and forth along one axis of motion and the tool is moved back and forth along another axis of motion perpendicular to the first axis. Such a machine is disclosed in U.S. Pat. No. 4,994,008 which issued Feb. 18, 1991 to Haake et al. The '008 patent discloses a machine having a large table for receiving a sheet of material. The sheet of material is fed through an operating unit that includes several tool heads that operate on vertically disposed slides for performing the various manufacturing operations on the sheet. As the sheet is fed back and forth along one axis the tool heads track along horizontal lines, and as the sheet is held stationary the tool heads move up and down vertically to track along vertical lines. The tools, however, engages only one side of the sheet of material when performing their manufacturing operation pressing the material of the sheet against the flat surface of the table. Therefore, when creasing for example, the crease is simply an indentation in the outwardly facing surface of the sheet. When the sheet of material is relatively thick and stiff, or hard, as the blank is made to bend about such a crease the outer portions of the surface of the sheet at the bend tend to fracture and split. To overcome this problem mating upper and lower dies are used in a press to form crease lines that are indented on one surface and are out-dented on the opposite surface. This provides sufficient displaced material along the crease line that, when bent, there is no fracturing or splitting. However, such dies are relative expensive to manufacture and a unique set of dies is needed for each different size and shape of box or other item being manufactured. Therefore, such dies are not economically suitable for use in making samples in low quantities.
What is needed is a machine capable of forming a crease line having an indent in one surface and an out-dent on the opposite surface formed by tools that concurrently engage both sides of the sheet of material, wherein the tools and the sheet of material undergo relative movement in first and second mutually perpendicular directions. The movements of the tools in tracking the desired crease lines should be computer controlled and the tools quickly changeable for fast, economical manufacturing of low quantities of boxes or other items.